Electrical connector



June 15, 1954 R. c. swr-:NGEL 2,681,440

ELECTRICAL CONNECTOR Filed Nov. 19, 1951 T'lc'l.

T1 :1.11 b. /J m BY d @www ATTORNEYS:

Patented June 15, 1954 UNITED STATES @GFFICE ELECTRICAL CONNECTOR RobertC. `Swensel, iYork, lia., aassienor to Aircraft-Marine ProductsIncgHarrisburg, Pa., a corporation ,of New Jersey Application November19, 1951, Serial No. 257,080

11 Claims. (Cl. 339-223) This invention relates to electrical connectorsand particularly to improvements v,in such con.- nectors whereby theconductive parts of the connectors are insulated, for the purpose amongOthers 0f Dreventngnflash-cyer between connectors. The invention`further relates to insulated electrical connectors having particularlystrong and secure engagement not only between the connector andelectrical `conductor but also between the insulating member or coveringand the electrical conductor.

Modern industrial and military `electrical equipment creates a demandfor electrical con.- nectors offering the utmost in dependability,particularly among other things that the terminals be insulated, that isthat the connector be insulated ffor ,a vdistance back along theelectrical conductor. The purpose of this insulation, among others is toprevent creepage current on the surface of the insulation and ashoverbetween adjacent connectors, which might otherwise result 'from voltagesurges, ionizing conditions in the atmosphere or dampness etc., or fromaccidental movement of the connectors too close to one .another or toother conductor elements. Such leakage from electrical connectors could,of course, result in failure of equipment at a critical time and this isof cou-rse particularly signicant in connection with military equipment,railroad signal equipment, aircraft,ietc. Inthe past even insulatedconnections 'have in some instances been subject to such failure.

fThe primary ,object of the invention is to provide `an electricalAconnector having improved insulation characteristics. Another object`is to provide a connectorhaving improved attachment of the insulatingmember or material tothe `electrical conductor to provide secureengagement therewith, and With shielding thereon when used. Anotherobject is to provide an increased insulated `distance from theconductive parts of the connector, increased creepage distance andgreater resistance to iiash-over from the `conhector.

Although in the accompanying drawings I have shown a preferredembodiment `,of my `invention and have described -the same andsvarious.modincations thereof `in this specification, it iis to be understoodthat these are not intended tobe e-xr haustive but, on the contrary, areJclfiosen Yfor Ethe purpose ofillustrating the invention in order thatothers 'skilled ,inthe art may so ifully vouderstan.d the invent-ion,its principles and the application thereof that they :may embody it and.adapt fit f of Aa `yvire.

2 numerous forms, each as may be `best suited vto therequrernents of itsparticular use.

Further objects and numerous advantages of the inyention will becomeapparentfrom the iollowng detailed description and `annexed drawingwherein;

Figure 1 is an electrical terminal -haying an enlarged insulating tubeand a supporting `metal han@ within the tube.

Figure 2 is similar'to Figure 1 but With the end of the metal band spunback oyer the insulating sheath.

Figure 3 is a sectional viewtof a preferred form of the intentionwherein there is a metal supporting band spaced lQm the sleeve `aroundthe ferrule..

Figure 3a is a vfragmentary sectional viewshow.- ing a modincation `ofFigure 3.

Figure 3b isla fragmentary sectional view show`- ing .anothermodiiication of Figure 3.

Figure 4i is a sectional View taken along line LA f Figure "3.

"Figure f5 is a perspective View of the `form of the invention `of`Figure 13 crimped onto 4the Lend :Bientot is a .modified .form of theinvention applied to a shielded wire in Aa way to isolate the shielding,from the terminal- :Fisuso 'i is a perspective VView of :thearrangement o f gFgurelG crimped onto a wire.

Fiel-iro `8 is a fragmentary View axial sect-ion of a connector similarto that ,of `.Figure V3, but with extended :wire supporting portion andwith on .insulated shielded Wire inlolaoe therein ready for orimpina Assstiorth inthe foregoing objects, tno invention soolss to prov-ido animproved insulatedioonneetcr, by reason among `'other things `ofprovid,- ing yarnoyel and improved manner and means of securing rtv-iretherein. -In addition, the 4intentieyn provides more iapp-ropriate and`eiectiy` `,support for the insulation wh-ioh normally is the torm of asheath .oVer `the Wire.

Referring :i0 Figure l of the drawings, there Y is :shown an oleotrioalconnector comprising ,a

ferrule I2 and a connector-tongue portion t4. `'The ferrule 1.2 is`tor-med A:by material 'rolled into oy1 i r1 drical tor-m withlongitudinal abutting edges nhicnfmay bsbrozod together. `liuiooraliones..- enaies @a plastic tube engaging .forrule 1 2 and advantageouslyoomonted thereto, :in aooordanoo with the invention .disclosed and.claimed :in lmy copensiine :application Serial 251,466 tiled Qotoberi6., .11;951., VnowPatent No. -2 ,654,852'3, issued .Qotoberfa 12253.fine emisor tube It :issemareed as shown at I8 to receive an insulatedwire, the end of which is stripped and crimped in the ferrule I2, e. g.,by a crimp of the type disclosed in the patents of Buchanan Nos.2,379,567 and 2,554,813, or of the Carlson Patent No. 2,359,083, or ofthe I-Ioltzapple application Serial No. '73,946 filed February l, 1949.The portion I8 is enlarged to permit reception of an insulated(unstripped) portion of the insulated wire within the end portion of theinsulating tubing and this may be crimped so that the tubing securelyengages the insulation of the wire.

Within the enlarged portion I8 is a metal band 20 which when crimpedsecurely engages the insulation of the wire. The type of crimp may beone well known in the art. The portion I8 is of somewhat larger diameterthan the insulated wire and the preferred type of crimp is one whereinupper and lower portions of band 2B and portion I8 assume a curvedcontour and side portions are more or less parallel, as in saidapplications of Carlson and Holtzapple, respectively, thus providingsecure engagement with the insulated wire. The band 20 serves thepurpose of providing support for the insulating tubing I6 before it iscrimped; and the tubing I6 being securely cemented to it, it helps tohold the exterior of the wire when the connection is crimped on. Theband 20 enables the tubing to assume and retain the desired shape and toserve its intended purpose most effectively.

The plastic tubing I6 may be formed and applied in any of various waysaccording to the various methods used in the plastics art.

Figure 2 shows an arrangement similar to that of Figure 1 wherein themetal support band 20a within the enlarged portion I8 of the insulatingtubing I6 extends back over the end of the tubing as shown at 24. As inFigure 2 band 20a is securely attached by crimping to the insulated wireand the insulating tubing I8 is cemented to the band. The turned overportion 24 further assists as a retainer for the insulating tubing I8,securing it in position and holding it against changing form in responseto plastic memory, e. g., if the terminal should become overheated.

Figure 3 is a view of another advantageous form of the invention whichprovides a very effective insulated connector. Numeral I2 indicates aferrule having a connector portion I4. ferrule is formed of pureelectrical copper by rolling a blank stamped from the sheet materialinto cylindrical form such that a longitudinal butt joint is formedalong the top thereof. Over the ferrule thus vformed is tted a seamlesscopper V(or other metal) sleeve 28 which extends .beyond the end of theferrule. The sleeve 28 is necked or indented as indicated at 30, andcrimped over at its opposite end as indicated at 32. Numeral IIbindicates a plastic sheath applied around the outside of sleeve 28 andextending beyond it for purposes of insulating the terminal. Inside ofthe extension I8b of sheath |619 near its end is a metal band 2Gb whichserves as a support for the Vend of the sheath I 6b and to which thesheath is securely cemented.

In use the ferrule I2 is crimped to a bare part 34 of an electricalconductor in a manner well known in the art and the extending portion I8of the sheath I6 and the band 20 are crimped in a known manner to aninsulated part 36 of the wire as shown at 31, the band 20 securelyengaging the insulation. The sheath I8, being securely cemented to theband 20 maintains the same shape as the band. (I use the reference Thenumerals generically to refer to the corresponding elements of themodified forms of Figures 2-8, as well as the form shown in Figure 1.)

Figure 3a shows a modification of the structure of Figure 3 in which theband 20c is on the outside of sheath Ib instead of inside, but providessupport for it in the same manner as in Figure 3. The band is fitted onand cemented to the sheath I8?) as in the previous embodiment.

Figure 3b shows another modication wherein a stepped band is usedinstead of the simple band 23h. The inner portion of this band is usedlike its counterpart 20h of Figure 3; while the outer portion 38 canreceive an outer insulation, where used over the shielding. When theinner portion and the end of sheath I8b are crimped, e. g., as shown inFigure 5, for the embodiment of Figure 3, those two parts areinterlocked, and the shielding is securely engaged. When the outerportion 38 is crimped it securely holds the outer insulation of thewire, holding it against pulling back so as to expose any part of theshielding and also avoiding any unsupported area where repeated flexingmight cause a fatigue failure in the wire.

Figure 5 is a perspective view of a terminal as shown in Figures 3 and 4when it has been crimped onto the end of an insulated wire. As will beobserved, the conductor is shown of the multi-strand type (although itmight be solid or single strand). The end of the ferrule I2 and thesleeve 23 and 4sheath Ib are crimped as shown to a more or lesselliptical shape by a compression forging process as already known inthe art. The crimping tool leaves twin indents on each side with atransverse ridge between each pair on the upper and lower sidesrespectively, as shown. The opposite end of the sheath I 8b and band 2Gbare crimped onto an insulated part of the wire as shown at 31,preferably by a conned compression die of the type shown in said Carlsonpatent. The resulting construction is a thoroughly insulated connectorwherein the insulation is firmly secured to the connector and canj notslip therefrom. The connector is furthermore fully protected fromflash-over in that the metal band 23h secured to the outer end 0f theinsulating sheath is not connected to any conductive part of theassembly.

Referring to Figure 6 of the drawings, there is shown another form ofthe invention applicable particularly to shielded conductors, whereinthe connector itself is insulated from the shielding; yet the shieldingis secured thereto without taping and shellacking. In Figure 6 theferrule I2 and connector are secured to the plastic sheath Id bycementing it to the sleeve 28d and/or crimping the latter thereon. Metalsleeve 23d engages the ferrule I2 and the outside of the end of sheathI8cZ. Sleeve 23d is necked or annularly indented as shown at Sd. Theband 28d in this case extends beyond the end of sheath ISd to receiveand engage shielding or other part of the wire.

The ferrule I2, sleeve 23d and sheath IBd can be crimped onto the wire34 and insulation 35d in a manner corresponding to that of previousembodiments or in other ways known to the art. The wire of Figure 6 isof the type having braided metallic Wire shielding 55 which is normallygrounded. The metal band 29d is secured to the end of the sheath iSd asin the other gures, and after insertion of the wire into the connectorthis band is crimped onto the adjacent ends of sheath ISd and shieldingmaterial 56, e. g., as previously described, so as to firmly secure theshielding to the connector,

Figure 7 is a perspective View of the arrangement of Figure 6 afterbeing thus crimped to a Wire. As Will be observed, the arrangementprovides a very effective insulated connector particularly for insulatedwires having shielding thereon, the arrangement thoroughly insulatingthe shielding from the terminal itself but all of the parts of theassembly being very securely attached to the Wire.

Where the wire to be connected is composed of several coaxial layers thesheath i8 and/or the band 2li may be stepped in additional steps tosupport or secure successive layers. Thus with the structures of Figures1 or 3, the plastic I8 may be extended farther and enlarged to a greaterdiameter to receive the next largest layer, With or Without acorresponding extension and enlargement of the supporting band 2B; orthe band 2l! may be thus extended and enlarged beyond the end o theplastic sheath I8. Or a larger tube of metal or insulating plastic canhave one end iitted and secured to the outer end of such a connector andits other end of a size to receive and hold one of the layers of theWire.

This is illustrated by Figure 8 wherein a larger insulating sheath 58 iscemented onto the end of sheath |81) of Figure 3. This connector isshown assembled with, but not yet crimped onto a multilayer wire havinga central conductor 34, insulation 36, shielding 5B and externalinsulating layer 60.

I claim:

1. In an electrical connector, in combination, a ferrule of malleablemetal having an extending connector portion, said ferrule comprisingmalleable conductive material, a coating of nexible insulating materialof the type adapted at room temperature to transmit Without failureforces sufficient to forge said malleable metal together with aconductor into secure engagement, said coat being permanently secured onsaid ferrule, and a malleable metal band secured to the insulating coatnear its end remote from said eX- tending connector portion, the ends ofsaid band being axially displaced from the near end of said coat andinsulated from all conductive parts in contact with said ferrule.

2. In an electrical connection the combination as defined in claim 1Which further includes an insulated wire, said ferrule being forged ontoa central conductor of the Wire in electrical contact therewith and saidband and the portion of the insulating sleeve secured to it beingcrimped into engagement with a portion of the Wire where its insulationremains intact.

3. In an electrical connector, in combination, a ferrule forming portionof malleable metal having another connector portion extending therefrom,an extension of stiiily flexible insulating material secured to saidferrule at its open end, said insulation extending beyond all metal inconductive relation to the ferrule, and a malleable metal band securedthereto in an area at the end of said extension and spaced beyond saidferrule portion.

4. In an insulated electrical connection, in comblnation, a metalierrule, a shielded, insulated electrical conductor having an endsecured in pressure engagement in the ferrule, a coat of insulatingmaterial secured to the ferrule and extending therebeyond, the shieldingmaterial on said conductor terminating beyond the said ferrule andspaced by said coat from all parts in conducting relation With theferrule, and a metal band secured to an end portion of the insulatingcoat and surrounding said shielding material and crimped to securelyengage it.

5. In an insulated electrical connection, in combination, a metalferrule, a shielded, insulated electrical conductor having an endsecured in pressure engagement in the ferrule, a coat of insulatingmaterial secured to the ferrule and extending therebeyond, the shieldingmaterial on said conductor terminating beyond the said insulating coatand spaced from all parts in conducting relation With the ferrule, and ametal band engaged over adjoining portions of the insulating coat andshielding material.

6. In an electrical connector, in combination, a ferrule having anextending connector portion, an insulating coat engaged over the ierruleand extending therefrom, and a metal band secured thereto Within saidextending portion and spaced from all parts in conductive relation tothe ferrule.

7. In an electrical connector, in combination, a ferrule having anextending connector portion, an insulating coat engaged over the ferruleand extending therefrom, the extending end of said coat being enlarged,and a metal band secured thereto within said enlarged portion and spacedi from all parts in conductive relation to the ferrule.

8. The structure of claim 7 wherein the metal band extends beyond theend of said coat and back over its exterior.

9. In an electrical connector, in combination, a ferrule having anextending connector portion, an insulating sleeve engaged over theferrule and extending therefrom, the extending end of the sleeve havinga metal band iitting thereover and spaced from all parts in conductiverelation to the ferrule, the band being secured to the sleeve.

l0. The structure of claim 9 wherein the ferrule is securely crimpedonto a bare portion of an electrical conductor and the tube and metalband are securely crimped onto an insulated portion of the conductor.

1l. An electrical connector comprising a cylindrical malleable metalferrule, a tubular insulator extending coaxially from one end of saidferrule, a coaxial sheath engaging adjacent portions of said ferrule andinsulator securing said ferrule and insulator together, and acylindrical malleable metal band surrounding said insulator at leastnear its end remote from said ferrule, said band extending beyond theremote end of said insulator.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 2,316,267 McLarn Apr. 13, 1943 2,405,111 Carlson et al Aug..6, 1946 2,410,321 Watts Oct. 29, 1946

